The SR503-4 from Taco is a 3-Zone Switching Relay with Priority. It combines clearly labeled PC board layout with advanced features that allow for total system customization. External indicator lights provide instant diagnostic feedback, making a snap of service calls or new installation start-ups. Taco SR503 switching relays are UL and CSA listed, use standard “ice cube” replaceable relays and are compatible with conventional and programmable thermostats.

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Shop the widest online variety of PEX, plumbing, heating, and HVAC supplies at Canarsee. We carry everything for a residential project of any scale, at the lowest prices on the market. If you have any questions just ask our knowledgeable staff!